Illuminated sign for day and night display



April 23, 1935. H. WOLFF ILLUMINATED SIGN FOR DAY AND NIGHT DISPLAYFiled July 24, 1953 atented Apr. 23, 1935 PATENT OFFlCE 1,998,857ILLUMINATED SIGN FOR DAY AND NIGHT DIS PLAY

Hendrik Wolff. Voorburg, Netherlands Application July 24, 1933, SerialNo. 681,974 In the Netherlands March 27, 1933 3 Claims.

This invention relates to improvements in signs for day and nightdisplay and has for its object to provide a device of this characterwhich, when illuminated at night by an incandescent or other type oflamp, presents the attractive appearance of a luminous neon tube.

A further object of the invention is the provision of a sign having suchstructural characteristics that the letters or other figures thereon areclearly visible in ,the daylight.

A further object of the invention is the provision of a sign of thischaracter which is of simple and inexpensive construction.

Further features and advantages of the invention will become clear fromthe following descrip-v tion and accompanying drawing in which Fig. -1illustrates a transparent sign according to the invention'when beingilluminated by direct light.

Fig. 2 illustrates the same sign illuminated by transmitted light withthe aid of a source of light arranged behind it.

Fig. 3 is a view in section taken on the line 3--3 of Fig. 2 on a largerscale.

Fig. 4 is a view in section corresponding with that of Fig. 3 of amodification of the invention.

Fig. 5 is a fragmentary perspective view of the improved sign positionedin a casing.

By way of example Figures 1 and 2 illustrate an N. The transparent signcomprises two glass plates I and 2. The sign figure designated generallyat 3 is visible in the desired colour and a similar mark 4, preferablygold-coloured, serves as a back ground. Fig. 1 shows how the letter isvisible by daylight and Fig. 2 how it is visible by night or whenilluminated from a light source 20. According to Fig. 1 the letter Nlooks like an ordinary flat letter Whereas Figure 2 shows that theletter when illuminated by the light source becomes visible as acorporeal mark, having height, width and thickness, and apparentlystanding out from the back ground. The back plate 2 may be covered by athird'glass plate 6 (Fig. 3) for protecting the coats of paint.

In Fig. 3 one of the legs of the letter N is illustrated on a muchlarger scale and in section. On the back of plate I the sign figure 3 ispainted in the desired colour in a thin translucent coating 1 and thisfigure is covered by a white, translucent and reflecting coating 8.

The back of the second plate 2 is covered by an opaque gold coating 9having the shape of the figure on the plate I. A portion l0, however,having a smaller width than the coating of paint 1 and preferably halfthe width of the latter is not covered. The back of the gold coating 9and the remaining portions of the back of plate 2, except for portion10, are now painted with a coating of opaque black paint H. Thereafterthe entire back is covered by a translucent gray coating l2 which passesa diffused light through the portions I0. On the back of plate 2 theprotecting plate 6 of ordinary glass is arranged in such a manner thatall coatings of paint are enclosed and cannot be damaged by dustormoisture.

When light is thrown through the sign a beam of diffused light passesthrough the coating l 2 and the portion l 0 and a portion of thisdiffused light passes throughthe medial portions of the coatings 0 and Ithereby illuminating the sign figure. Another portion of the light isreflected rearwardly by the coating 8 upon the gold coating 9. Thelatter reflects the light along the edges of the coatings 1 and 8. Thewidth of the beam of light passing through the portion l0 being smallerthan that of the coating 1 and being preferably equal to half the saidwidth, the central portion of the last mentioned coating is illuminatedto a larger extent than the marginal portions thereof so that in thesaid portions a shading will be efiected which gives the letter theappearance of a round form so that it seems that it lies like an objecton the black background H. The light reflected by the gold coating 9increases the said effect considerably.

Since there is between the coatings 1 and II a certain distance which isalmost equal to the thickness of the glass plate it appears to theobserver that the sign figure stands out in the space like a luminoustube. It is characteristic of the sign according to the invention thatwhen the light passes through it, the background becomes entirelyinvisible so that by night the casing or the like in which thetransparent sign is used is visible.

It is possible for the reproduction of a letter in white light, toemploy a third plate arranged between the plates l and 2 (Figure 4) Onthis third plate the black background II is arranged which for a betterreflection is covered by a coating M of a light green colour. The otherpaint coatings on the plates 1 and 2 are arranged in the same manner asdescribed with reference to Figure 3. If desired the third plate I3 maybe provided behind the centre of the sign figure with a narrow coatingI5 of yellow, which passes the light and reflects it at the same time.The breadth of this coating I5 should be smaller than that of theportion I0.

The transparent sign according to the invention may be mounted in acasing 2| of any construction in which the lamp 20 is located and inpractice it has been found that only one or a few incandescent lamps 20of a normal voltage are required for an effective illumination.

I claim:

1. An illuminated sign for day and night display comprising a signfigure of translucent. material, an opaque element having a translucentarea conforming in shape to the shape of the sign figure, arranged atthe rear thereof and 'of less width than said figure, and a source oflight arranged behind the opaque element, the narrow translucent areaconfining the passage of the light from said source to the medialportion of said figure, a partially reflecting surface behind the signfigure and a reflecting surface in front of the opaque element outliningthe translucent area for reflecting light received from the partiallyreflecting surface toward the marginal areas of the sign figure.

2.'An illuminated sign comprising a source of light three plates ofglass disposed in front of the source of light; the front plate havingon its rear face first a layer of translucent material and secondly'alayer of partially reflecting and translucent material superimposed onthe first layer, the two layers constituting the sign figure; the middleplate having on its rear face a layer of refleeting material outliningthe translucent area and conforming in shape to the shape of the sign'figure, secondly a layer of opaque material outlining the refiectingmaterial and thirdly a coat of diffusing material completely coveringthe rear face; and the back plate protecting the first two plates.

3. An illuminated sign comprising a source of light four plates of glassdisposed in front of the source of light; the front plate having on itsrear face a layer of translucent material constituting the sign figureto be reproduced; the second plate having on its rear face first a layerof opaque material outlining an area similar to but larger than the signfigure, secondly a layer of reflecting material superimposed on thefirst layer and also on its rear face a layer of partially reflectingand translucent material conforming to the shape of but smaller than thesign figure disposed substantially behind the layer of translucentmaterial on the rear of the front plate; the third plate having on itsrear face a layer of reflecting material outlining a figure similar tobut smaller than the sign figure on the first plate and larger than thelayer of partially reflecting and translucent material on the sec-- ondplate and a coat of diffusing material completely covering the rear faceand the back plate protecting the other three plates.

HENDRIK WOLFE. Y

